Our big brains may make us prone to cancer

NewScientist (Oct. 15, 2012)

There’s a downside to everything. When humans evolved bigger brains, we became the smartest animal alive and were able to colonise the entire planet. But for our minds to expand, a new theory goes, our cells had to become less willing to commit suicide – and that may have made us more prone to cancer.

By getting rid of malfunctioning cells, apoptosis also prevents cells from growing into tumours. “Reduced apoptotic function is well known to be associated with cancer onset,” says John McDonald of the Georgia Institute of Technology in Atlanta.
McDonald compared skin cells from humans, chimpanzees and macaques and found that, compared to cells from other primates, our cells are reluctant to undergo apoptosis. When exposed to apoptosis-triggering chemicals, human cells responded significantly less than the chimp and macaque cells. Fewer human cells died, and they did not change shape in the ways cells do when preparing to die. (full story..) (link to paper)